1. Field of the Invention
The present invention relates generally to cameras and, more specifically, to techniques for spatially locating images from cameras based on distance measurements to features in the images.
2. Description of the Related Art
Often, users of electronic devices, such as personal computers and smart phones, wish to view on their electronic device the interior of a building or other man-made or natural structure that establishes an indoor space. For example, a device user may wish to view on their device the interior of a store that they are considering visiting, a cave that they are considering exploring, a facility that they are considering renting, or a room about which they are curious, e.g., a room in an art gallery or a museum. Users also often desire to see different views from different locations within these and other indoor spaces. Seeing the indoor space from different perspectives generally provides the user with a more accurate sense of the layout, features, and other attributes of the indoor space than an image from a single perspective.
Indoor spaces are sometimes characterized with spatially-referenced images, which in many instances, depict the interior of the indoor space from different locations. Generally, the different locations are associated with the images such that images may be selected, arranged, or otherwise presented based on (e.g., based at least in part, or based solely on) the location from which they were captured. In some instances, users of electronic devices may tour or otherwise explore an indoor space by viewing images from different locations within the indoor space and virtually moving through the space by selecting different locations near the location from which they are currently viewing the indoor space.
In some systems and some use cases, it is difficult to determine the location from which an image is captured within an indoor space. Indoor spaces are typically more challenging to spatially reference than outdoors, where location is often determined based on global positioning satellite signals or based on the wireless environment. But indoors, these location-indicating signals are often attenuated, impeding efforts to identify the location from which an image is captured. And other techniques for identifying the location of images within an indoor space are often expensive. For example, the location of a camera may be measured relative to some reference point by manually measuring distances to the reference point with a measuring tape, but this technique is often slow and labor intensive. In another example, location may be determined by scanning substantially all of the surfaces within the room from the location of the camera in order to form a three-dimensional map of the room and identify the position of the camera within that three-dimensional map, but three-dimensional scanning systems are often expensive relative to the cost of the camera due to the complexity of the hardware used to scan the room and process the scan data. Consequently, locating images within indoors spaces is often expensive, either due to the cost of labor or the cost of the equipment.